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F. I-I. RICHARDS. MACHINE PoR, MAKING TWIST DRILLS.

Patented June 30, 1885.

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Ik vfe' nzbij IMQ 6%@ @wwf ERANCIS H. RICHARDS, oF CLEVELAND, orne, ASSiCNoR To J. D. COX, JR.,

AND E. E. rREN'rISs, ROTH on SAME PLACE.

MACHINE FOR MAKING TWIST-DRILLS.

SFIECIFICATION forming part of Letters Patent No. 320,968, dated June 30, 1885.

Application tiled August 15, 1883. (No model.)

T0 all whom, it may concern:

Be it known that I, FRANCIS H. RICHARDS, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented Improvements in Maehinesfor Making Twist-Drills, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates more especially tothe making of that class of twist-drills in which the grooves have an increasing pitch and an increasing cross-sectional area from the point ofthe drill toward the shankthereof'.

The objeetof my invention is, chiefiy,t0 provide means for forming the grooves of twist'- drills to have a more perfect ratio or increment of increase in the pitch thereof for forming said grooves to have an increasing crosssectional area from the point of the drill toward the shank thereof, and for making the grooves in a series of sizes of drills by a corresponding series of adjustments of the same mechanism at the same time preserving the aforesaid ratio of increase of the pitch thereof.

For the attainment of these objects my'invent-ion consists in, certain mechanism, hereinafter described, for forming the grooves in twist-drills, in whichv the pitch of the said grooves made in a drill by means of said mechanism is determined by the pitch of the groove of a patterncylinder, forming, for the time, a part of said mechanism. lt also consists in the nature of the curve of the said patterncylinder groove, whereby it is made to more perfectly perform its function of determining the pitch of the grooves of a series of sizes of drills.

Referring to the drawings, Figure l is a side elevation of a twist-drill-milling machine embodying my improvements with the parts adjusted to a position for milling the grooves of large drills. Fig. 2 is a similar view showing the parts as adjusted for milling the grooves of smaller drills than in the previous iigure. Fig'. 3 is a detail of Figs. 1 and 2. Fig. 4 is an enlarged plan view of a drill,show ing the position of the milling-cutter in the two positions relative to the same. Fig. 5l is a diagram to more clearly show the axes, eenter lines, and angles of Fig. 4. Figs. 6 and 7 are sections of the drill shown in Fig. 4 inlines ww and y y, showing the relative cross-sectional area of the grooves at these points. Fig. 8 is a section of the drill near its point, and Fig. 9 is a section of the blank for the same before the forming of the grooves therein. Fig. 1() is a view, on a reduced scale, relative to Figs. 4 to 9, inclusive, showing the kind of curve employed for the groove ofthe patterncylinder. Fig. 11 is a similar view showing a curve made in an arbitrary manner, in order to explain by contrast the curve in Fig. 10, and Fig. 12 is al view showing the application of the said former curve to the forming of said groove. Fig. 13 is a detail of Figs. 1 and 2.

In the drawings, F is the frame of a twistdrill-milling machine having standards A, A', and A2 formed upon or secured thereto rigidly or ad j ustably, as preferred.-

B is the bushing that supports the drillblank D to the action of the milling-cutter C', which is carried by an arbor, S. (Only partially shown.) is not shown, but it may be of any construction suitable to hold and properly raise the same during the milling operation in the usual manner.

The mechanism I prefer to use for support- -ing and operating said spindle is shown in United States Patent No. 286,150, Figs.v 1, 2, 6, and 7. This mechanism during the operation of cutting a groove moves the cutter Slowly away from the blank for the purpose of forming the drill with a center of increasing thickness from the point toward the shank thereof; but it does not vary the angle ofthe cutter relative to the drill-blank. Theentter may and usually does, unless the drill is very large, iinish the groove by a single cut. This may be done and the groove So made still have an increasing width sufficient to produce an increasing cross-sectional area thereof from the point toward the shank of the drill, provided the milling-cutter has the proper size and position and the pattern-cylinder groove has a sufficiently-increasing pitch, regard being had to the diameter and size of groove of the drill-blank to be operated upon. Said diameter and the ratio of increase of the pitch may be readily formed experimentally or by The bearing for said arbor S IOC W'hen the cutter is near the point of the drill,

as seen in the direction of line d d, said cutter and shape of drill-groove appear as in Fig.

7 but when near the shank, and seen in the' direction of line e e', (this line being supposed to be tangential to the drill-groove at this point,) said cutter and groove will appear as in Fig. G, and the width z of the groove Will obviously be greater than shown in Fig. 7.

The bushing B is shown enlarged in proieclion in Fig. 13 as held in A2 by clamping, and having formed therein spiral enlargements R to allow the ridges on the drill-blank lo pass through, leaving the surfaces L to sup port the said blank by the cylindrical portion thereof only. The spiral enlargements R are made wider than the ridges ofthe drillblank, because ofthe different degrees of spirality of said ridges at different points in their length. In the top of bushing B an opening, N, Fig. 13, is made, through which the milling-cutter has access to blank D.

The spindle S is provided at E with a suitable socket, chuck, or other device to hold the drill-blank D and with a gear, G, whereby it is rotated. It is supported at one end by bearing A, and its opposite end passes centrally through and is supported by the pattern-cylinder O, which is supported in a bearing in standard A. rlhis cylinder O has a spiral groove, G, formed therein of a geometrically-increasing pitch uniform with the pitch of the drill-grooves to be formed by the machine.

On the top of A is a boss, H, in which a thimble, I, is secured by a set-screw, as shown, or otherwise, as may be preferred, for holding in place the swivel resistance-pin J, which is of a shuttle-shaped form at its lower end and lted to slide in the groove G of cylinder O, and to revolve in I to conform to the varying pitch of the said groove as the said cylinder slides by it.

A long pinion, P, meshing with gear G of spindle S, is supported in bearings A A', and

carries a worm-wheel, G2,which is acted upon by worm W, carried in bracket-bearing M. Power being applied to\\V, the worm-wheel G2 and pinion P are thereby rotated, and by means of the latter and gear G the motion is communicated to spindle S at any point of4 thereto.

its longitudinal movement.

In operation the pattern-cylinder O is so adjusted to position upon spindle S that such a portion of the groove G shall be operative to move the said spindle longitudinally during its rotation, as is uniform in pitch with the required pitch of the grooves to be made in the drill-blank D. It will be noticed that Figs. 1 and 2 are alike except in the position of pattern-cylinder O upon spindle S, and the size of the drill-blank being grooved. InFig. 1 a portion, U, of the groove Gis shown as being used forl a large-sized drill, and in Fig. 2 another portion, V, thereof is shown as being used for a proportionally smaller one. For an intermediate size still another portion, as X, of the pattern-groove would be selected. Thus, by a series of simple adjustments of the pattern-cylinder O upon spindle S, different portions of the same pattern groove G are made operative, as described, thereby enabling the machine to be used for grooving a series comprising a considerable number of drills without a different pattern cylinder.' The pattern-cylinder O being now rigidly secured in proper position upon spindle S and a proper motion applied to W, it is obvious that while the gearing described acl's to revolve said spindle S, the pin P and` groove Gwill operate to impart a simultaneous longitudinal movement thereto having a velocity relative to the velocity of rotation, proportional to the pitch of that portion of said groove traversed by said piu P, thereby feeding drillblank D to the action of millingcutter C, to form grooves therein uniform in pitch with the said portion of groove G.

q In order to form the groove G in the pattern-cylinder to have such a curve as required to properly accomplish the object of my inlvention, I proceed as follows: Upon a sheet of suitable material the curve 11 12 13, Fig. 10, is so laid out that if the4 space between it Aand the baseline 9 10 is divided by ordinates at equal distances apart, as l 2 3 4 5 6, the length of said ordinates will be in geometrical progression-that is to say, if the value of ordil nate 6 be multiplcd by the given ratio of the progression. the product is equal to the value of ordinate 5. The value of ordinate 5 being then multiplied by the same ratio, the resulting` product is equal to the value of ordinate 4, and so on as faras required. The curve is extended in the reverse direction by a similar process ofdivision instead of by multiplication. Thus, if the length of ordinate 6 equals 8 and the geometrical ratio of an increasing series is 1T() then the length of ordinate 5 will be equal to 8 1,-,0 :ii-,028% A sufficient length of the curve being determined, the sheet is next eut to the form shown at 9 10 11 1 2 13, and wound upon the plain pattern-cylinder, as shown in Fig. 12, so that the ordinates 1 2 3 4, &c., are parallel to the axis oi said cylinder, and the curve 11 12 13 forms the proper spiral lor the groove G, which is then made according A geometrical curve I consider superior to others for this purpose, because of this quality: Vhen each ordinate of one portion of the curve IOO IIO

ISO

is divided or multiplied by the salne number, the curve thus produced is identical with some other portion Lof the original curve. This result is represented in Fig. 10, where the ordinates1'2 3 4 5 of the curve 11 12 13 are divided by 2, producing the curve 7 8, which, being moved to the right a sufficient distance in a direction parallel to the base-line 9 10is found to coincide with another portion of the said curve 11 12 13, as shown at 7" 8.

O wing to the circumstance that a geomet-- rical curve has the above property, the manufacture of pattern cylinders, in which the grooves have a terminal pitch greater or less than the original, is greatly facilitated by havlng the groove of such original or master pattern-cylinder made according thereto. The said master pattern-cylinder being fixed in the place of the usual leading-screw in a suitable screw-cutting lathe. and the proper changewheels being employed, grooves may then be cut'in other pattern-cylinders of a greater or lesser pitch, as required. Thus, for instance, if the master pattern-groove is adapted for use in grooving drills of from three-fourths to one and one-half inches diameter, another may be made therefrom adapted for drills of from onefourth to one inch diameter, so that drills of from three-fourths to one inch diametermay 'be grooved by using the coarser end of the Vpattern-groove having the least .pitch or by using the finer end of that having the greatest pitch, as may be most convenient.

A pattern-cylinder having a groove of the curve herein described is adapted not only for A,use in twist-drill groove-milling machines,but

ployed other thanbushing B or its equivalent.

In order to illustrate still more clearly the peculiar advantagesl of a geometrical curve for the purpose herein described, I show in Fig.

' 1l another curve, 30 31, more nearly that usually employed and laid out in an arbitrary manner. By dividing similarly, as before,the ordinates 20 2 1 22 23 we obtain the curve 24 25, which, being moved in a direction parallel to the base-line 28 29 toward the ri ght,is found not to coincide with any part of the original curve 30 31. Pattern-cylinders, therefore, having grooves made conformable to such curve cannot be properly made or used in the manner hereinbefore described.

To obtain in practice for the curve 11 12 13, such as described a ratio great enough to form the groove G of a sufficiently-increasing pitch,

- so that the grooves made in the drill-blank which lines correspond to the positions of the milling-cutter at d d and c 0',Fig. 4. The size of Y the drill and angle of cutter now being known, v

a suitable cutter Ais next selected, preferably having a diameter between three and four times the diameter of the drill, and its form determined, substantiallyas described, in connection with Fig. 3 of United States Patent From these data the section x x, Fig. 7 is drawn, showing the Across-sectional area of the groove near-the point of the drill, corresponding to the form ot' the cutterselected. The width of another section of .the groove, yy, is next laid off at z, suiicient to secure the desired increase in its cross-sectional area at a point about one revolution of the spiral groove from the point where section x x is taken, Fi g.. 4, and the cutter is drawn therein at such an oblique projectiomwhich is determined by the usual method of f laying o ff by points from the form of Athe cutter as will form the said groove GV of theA designated Width. A lille c e, Fig. 5, is now drawn, makingtlie same angle with line c 0 as the plane of the cutter in Fig. 6 makes with the axis of the groove at the line where the section y 'y thereof is taken. Then theline e e' shows the pitchy of the groove compared with aXis a b of the drill at the point fi, about one revolution of the spiral from`point i. Now, referring to Fig. 10, lay off an ordinate, 6, which may be about equal tothe longest drill to be milled in the macl1ine,and fix one point,12, of

the required curve. Lay off V15 16,- equal tothe circumference ofthe pattern cylindendraw ing such questions.

' The bushing B is especiallyy designed for use when milling grooves in that kind of drillblank having in cross-section a peripheral outline, as shown in Fig. 9, which,wl1en the grooves are formed,appears as in Fig. 8, the said blank being of the general form of a cylinder, with ridges formed spirally thereon, and having the grooves G so formed therein as to make the cutting-edges e to be in the highest part of said ridges. A part of section c and a part of section G, Fig. 8, adjoining each other at are circular and concentric, as shown more clearly by comparison with the dotted size-circle passing through point, e, and is the portion of the surface of the blank that slides upon surface L of the said bushing. It is not necessary that the bushing B be made in one piece, but it may be in two or more parts, as preferred,

IOO

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secured in position in the machine in any suitable manner.

The* spindle S is shown herein as having a socket, E, for receiving'the shank of the drillblank D; but I do not limit myself to that construction,as any suitable form of chuck, clamp, or dog may be used inlieu thereof; but I have shown the form described merely to illustrate some means therefor.

I have herein used the expression a metalremoving device7 in referring to the millingcutter C for thev reason that theicombination of mechanism described is also designed for use in connection with a grinding-wheelV of any suitable kind as a substitute for said cutter in flnishing the grooves of drills previously formed by forging or otherwise. In this application I have shown and described the pattern-cylinder O to be adjustable upon spindle S for the purpose of bringing into use the different portions thereof, as required; but if the said cylinder were xed on said spindle-as, for instance,in the position shown in Fig. l, and the resistance-pin J was constructed to be similarly adjusted to the required positions, as U, V, or X', relative to said cylinder, it is obvious that the same result would be accomplished. I make no claim herein to such construction or adjustment of said resistance-pin; but in another application, Serial No. 103,851, I have described and claimed the same.

I do not claim, broadly, the combination of a metal-removing device and the spindle S having a pattern-cylinder adj ustably secured thereon, as I am aware such a combination has been used, the said pattern-cylinder having in that case a groove of uniform pitch throughout its length; `but I am not aware of such a combination having been used in which the said cylinder has a groove of increasing pitch, and is adjustable on said spindle, as or for the purpose herein described. Neither do I claim, broadly, a pattern-cylinder for twistdrill-making machines having a groove of increasing pitch, as I am aware such have been used; but Iam not aware that any such have been used heretofore in which the said groove is of a curve having ordinates in a geometrical progression, as herein described. I make no claim herein to the twist-drill nor the drillder herein described having the groove G of a pitch increasing by a geometrical ratio,substantially as described, andfor the purpose described.

2. In atwist-drill-making machine, the combination of a frame-work having bearing A and A', spindle S, a pattern-cylinder having a groove of a pitch increasing by a geometl rical ratio, said cylinder being adjustable longitudinally on said spindle, a resistancepin carried in bearings A and fitting said groove, and spindle-turning mechanism, substantially as described, foi` rotating said spindle S, substantially as described.

3. In a twist-drill-milling machine, the combination of the cutter C', formed substantially as described, a support, as B, for said drill, and drill holding and feeding mechanism,sub stantially as described, adapted to spirally feed the drill to the cutter, with a pitch increasing in geometrical ratio, substantially as set forth.

4. In a` twist-drill-making machine, the combination of the drill-holding spindle S, gear G', Xed thereon, the pinion P, meshing with said gear, and spindle-feeding mechanism, substantially as described, for imparting a longitudinal motion -to said spindle and gear, substantially as set forth.

5. The drill-supporting bushing B, having bearing-surfaces L and enlargements R, substantially as and for the purpose described.`

6. The combination of spindle S, gear G', pinion P, spindle-feeding mechanism, substantially as described, for imparting longitudinal motion to said spindle, Worm-gear G, Xed to said pinion, and worm W, substanj tially as set forth.

FRANCIS H. RICHARDS.

Witnesses: CHARLES O. PALMER, FRED J. DOLE. 

